Expansible underreamer



March 18, 1930. R 1,750,628

EXPANSIBLE UNDERREAIIER 1106 Oct. 15. 1928 2 ShOQtS-ShBGt l INVENTOR. 170/0270 Jf. 6/21/77.

A TTORNEYO' Patented Mar. 18, 1930 UNITED STATES PATENT OFFICE BOLAND R. OBUM, O]! WHITTIER, GALIIO BNIA, ASSIGNOR TO K. G. SMITH MANUFAC- TURING COMPANY, OF WHITTIER," CALIFORNIA, A CORPORATION 01 CALIFORNIA EXPANSIBLE UNDERREAMER This invention relates to an expansible underreamer having longitudinally extending cavities in its periphery and cutters accommodated therein for longitudinal play and lateral movement to effect expansion and contraction. The present invention appertains articularly to an expansion control means or guiding the cutters and retaining them in their several positions.

The objects of this invention are to provide an expansible underreamer of the character described having any or all of the following features :a catch on one end of a cutter to guide it in and out of'lateral expanded and contracted positions; a catch co-operating with a lateral bearing surface to laterally support a cutter in expanded position; a latch longitudinally movable and having a retaining surface to co-operate with a complemengo tary surface on the catch and retain the cutter against lateral displacement from the body; a latch as last specified, which, in its cutter expanded position, projects beyond the periphery of the body of the underreamer so as to beengageable by a casing shoe when the underreamer is pulled, and is movable thereby to cause collapsion' of the cutters.

These objects together with other objects and corresponding accomplishments are oba. tained by means of the embodiments of my invention illustrated in the accompanying drawings, in which Fig. l'is an elevation of an underreamer; Figs. 2, 3 and 4 are sections taken on the as planes correspondingly indicated in Fig. 1; Fig. 5 is a central longitudinal section through the underreamer with parts in collapsed position, a fragment of the well hole and the lower end of a well casing being shown; and Fig. 6 is a central longitudinal section showing the underreamer parts in expanded position.

Referring with more particularity to the drawing, a well-hole is s own with a casin 10 having a shoe 11 at the bottom thereo The underreamer is adapted to be lowered through the casing to a point below the shoe, where it automatically expands. In the embodiment shown herein, the underreamer is illustrated with three cutters, although it will be obvious that more or. less may be used.

As the cutters, and their associated parts are of like construction, it will not be necessary to describe more than one. The underreamer has a body substantially of cylindrical shape and marked 12. At the upper end the body is shown provided with a tapered threaded pin 13 for attachment of the tool to a drill string, and at the lower end is provided with a threaded box 14 for attaching the usual drilling tools such as a bit. Extending lengthwise through the body is a circulation passage 15 having communicating water courses to direct the wash to the working parts. In the body are longitudinally extending cavi-' ties 16 for the accommodation of cutters. At the bottom of each cavity is a pocket 17 for a follower or a propelling means for its cutter. At the upper endof each cavity is a ramp 9 comprising an inclined surface sloping outwardly and upwardly. In the body and above the ramp is a channel 18 for. a latch and pro viding alateral supportingsurface 19 for its cutter. At the upper end of each channel is a rider or offsetting plate 20 having a bevelled lower face 21. Each channel 18 has longitudinally extending mortises at their sides for receiving correspondingtenons on a latch.

In each cavity at its lower end is fulcrumed of a roller cutter shaft 23. The blocks are fulcrumed to the body by means of pins 24 extending across the cavities and disposed in elongated slots 25in the block. Each roller cutter shaft as shown is bent and has roller cutters or reamers 26 journalled thereon. Mounted upon the upper end of each shaft 23 is a block or catch 27 having a sloping bearing face 28. The tips of the catches are arranged to be engaged with the ramps 9. The catches have lateral faces 29 for enga e- 16511. with the supporting faces 19 on t e Eiich pocket 17 has slidably disposed there-- in a follower 8 housing a compression spring 30, the follower bearing against the lower on of block' 22 and urgin its cutter longitudinally upward. A lock1ole 31 is provlded 1n 1 the cap and a cooperating lock hole32 1n the a block 22 having a socket to receive the ends outer wall of the pocket for registration when the spring is completely compressed as shown in Fig. 5. The follower may be locked in compressed position by means of a pin 33 shown in Fig. 5. This pin ma be inserted when the underreamer is place in collapsed position preliminary to insertion in the casing. However, it is removed before the un derreamer is lowered.

A latch 34 with dove tails for the mortises is mounted in each channel 18. Each latch has a lower sloping retaining surface 35 complementary to the bearing surface on the catch. An inwardly sloping shoulder 36 is provided on the rear of the latch for cooperation with the ramp. In the construction shown, the latch is urged downwardly by its own weight.

In order to set the cutters in collapsed position, they are moved downwardly against the action of the compression spring 30 and the catches 27 are swung inwardly with their tips at the lower ends of the ramps 9 as shown in Fig. 5. The latches are disposed in their lower position with their shoulders 36 under the ramps 9 and their retaining surfaces 35 engaging the bearing surfaces 28. In this position, the cutters will be retained in collapsed position. However, the latches will be urged upwardly but held against such movement by the well easing bearing laterally against the latches. 'When the underreamer passes below the casing shoe 11 with the latches clear thereof, the latter are free to be moved laterally. The compression springs 30 expand pushing the cutters upwardly and causing the tips of the catches to ride outwardly over the ramps 9 to clear the latter. The latches are moved upwardly by the catches riding outwardly by reason of the shoulders 36 and bevelled upon ends 37, so that the latches are projected laterally rest.- ing against the riders 20, and the catches bearing against the supporting surfaces 19. The cutters are then retained in expanded position and against displacement as shown in Fig. 6. The tenons on the latches have a lateral clearance in their mortises to permit outward movement and riding of the latches onto the offset plates 20. i

What I .claim is 1. In an underreamer, the combination of a body having a longitudinally extending cavity in its periphery with an outwardly sloping ramp at one end, a cutter accommodated in said cavity for longitudinal play therein and having a connection to said body so that it may be moved laterally thereon into and out of expanded position, means tending to move said cutter toward said ramp, a catch secured to said cutter and having an outer lateral bearing surface, the tip of said catch engaging said ramp to cause said cutter to be retracted and projected upon longitudinal movement thereof, and a longitudinally movable latch on said body having a retaining surface complementary to and engaging the bearing surface on said catch to prevent outward lateral displacement of said cutter.

2. In an underreamer, the combination of a body having a longitudinally extending cavity in its periphery with an outwardly sloping ramp at one end, a cutter accommo" dated in said cavity for longitudinal play therein and having a fulcrum connection to said body at one end so that said cutter may be rocked laterally into and out of expanded position, means tending to move said cutter toward said ramp, a catch secured to said outter and having an outer lateral bearing sun face, the tip of said catch engaging said ramp to cause said cutter to be retracted and pro-- jectcd upon longitudinal movement thereof, and a longitudinally movable latch on said body having a retaining surface complementary to and engaging the bearing surface on said catch to prevent outward lateral displacement of said cutter.

3. In an underreamer, the combination of a body having a longitudinally extending cavity in its periphery with an outwardly sloping ramp at one end and a lateral support surface beyond said ramp, a cutter accommodated in said cavity for longitudinal play therein and having a connection to said body so that it may be moved laterally thereon into and out of expanded position, means tending to move said cutter toward said ramp, a catch secured to said cutter and having an outer lateral bearing surface, the tip of said catch engagin said ramp to cause said cutter to be retracted and projected and longitudinal movement thereof, said catch in expanded position overlapping and bearing against said support surface, and a longitudinally movable latch on said body having a retaining surface complementary to and engaging the bearing surface on said catch to prevent outward lateral displacement of said cutter.

4. In an underreamer, the combination of a body having a longitudinally extending cavity in its periphery with an outwardly slop-- ing ramp at one end and a lateral support surface beyond said ramp, a cutter accommodated in said cavity for longitudinal play therein and having a fulcrum connection to said body at one end so that it may be rocked laterally into and out of expanded position, means tending to move said cutter toward said ramp, a catch secured to said cutter and having an outer lateral bearing surface, the tip of said catch engaging said ramp to cause said cutter to be retracted and projected upon longitudinal movementthereof, said catch in expanded position overlapping and bearing against said support surface, and a longitudinally movable latch on said body having a retaining surface complementary to and engaging the bearing surface on said catch to prevent outward lateral displacement of said cutter.

5. In an underreamer, the combination of a body having a longitudinally extending cavity in its periphery with an outwardly upwardly sloping ramp at the upper end, a cutter accommodated in said cavity for longitudinal lay therein and having a connection to said ody so that it may be moved laterally thereon into and out-of expand-ed position, means tending to move said cutter toward said ramp, a catch secured to the upper end of said cutter and having an upwardly inwardly sloping bearing surface, the

tip of said catch engaging said rampto cause said cutter to be retracted and projected upon longitudinal movement thereof, and a longitudinally movable latch on said body having a retaining surface sloping complementary to and engaging the bearing surface on and engaging said catch to prevent outward lateral displacement of said cutter.

6. In an underreamer, the combination of a body having a longitudinally extending cavity in its periphery with an outwardly sloping ramp at its upper end, a cutter accommodated in said cavity for longitudinal play therein and having a connection to said body so that it may be moved laterally thereon into and out of expanded position, means tending to move said cutter upwardly toward said ramp, a catchsecured to said cutter andhaving an outer lateral bearing surface, the tip of said catch engaging said ramp to cause said cutter to be projected upon upward movement thereof into expanded position, and a longitudinally movable latch connected to said body so as to be moved laterally outward on its u ward movement and having a retaining sur ace complementary to and engaging the bearing surface on said catch to prevent outward lateral displacement of said cutter.

7. In an underreamer, the combination of a body having a longitudinally extending cavity in its periphery with an outwardly sloping ramp at its upper end, a cutter accommodated in said cavity for longitudinal play therein and having a fulcrum connection to said body at its lower end so that said cutter may be rocked laterally into and out of expanded position, means tending to move said cuttertoward said ramp, a catch secured to said cutter and having an outer lateral bearing surface, the tip of said catch engagin said ramp to cause said cutter to be projecte upon upward movement thereof into expanded position, and a longitudinally movable latch connected to'said body so as to be moved laterally outward on upward movement and having a retaining surface complementary to and engaging the bearing surface on said catch to prevent outward lateral displacement of said cutter.

8. In an underreamer, the combination of a body having a longitudinally extending cavity in its periphery with an outwardly sloping ramp at its upper end and a lateral support surface above said ramp, a. cutter accommodated in said cavity for longitudinal play therein and having a connection to said body so that it may be moved laterally thereon into and out of expanded position, means tending to move said cutter upward toward said ramp, a catch secured to said cutter and having an outer lateral bearing surface, the tip of said catch engaging said ramp to cause said cutter to be PI'OJGCtBd upon upward movement thereof into expanded position, said catch in expanded position overlapping and bearing against said support surface, and a longitudinally movable latch connected to said body so as to be moved laterally outward on its upward movement and having a retaining surface complementary to and engaging the bearing surface on said catch to prevent outward lateral dis placement of said cutter.

9. In an underreamer, the combination of a body having a longitudinally extending cavity in its periphery with an outwardly sloping ramp at its upper end and a lateral support surface above said ramp, a cutter accommodated in said cavity for longitudinal play therein and having a fulcrum connection to said body at its lower end so that it may be rocked laterally into and out of expanded position, means tending to move said cutter toward said ramp, a catch secured to said cutter and having an outer lateral bearing surface, the tip of said catch engagin said ramp to cause said cutter to be projecte upon upward movement thereof into expanded position, said catch in expanded position overlapping and bearing against said support surface, and a longitudinally movable latch conneeted to said body so as to be moved laterally outward on its upward movement and having a retaining surface complementary to and engaging the bearing surface on said catch to prevent outward lateral displacement of said cutter.

10. In an underreamer, the combination of a body having a longitudinally extending cavity in its periphery with an outwardly sloping ramp at its upper end, a cutter accommodated in said cavity for longitudinal play therein and having a connection to said ody so that it may be moved laterally thereon into and out of expanded position, means tending to move said cutter upwardly toward 7 said ramp, a catch secured to said cutter and having an outer lateral bearing surface, the tip of said catch engaging said ramp to cause said cutter to be projected upon upward movement thereof into expanded position,

and a longitudinally movable latch connected to said body having a retaining surface complementary to and engaging the bearing surface on said catch to prevent outward lateral dis lacement of said cutter said latch and sai body having engaging bearing surfaces stepped so that said latch will offset laterally outward in upper position and inset in lower position.

11. In an underreamer, the combination of 'a body having a longitudinally extending cavity in its periphery with an outwardly sloping ramp at its upper end, a cutter accommodated in said cavit for longitudinal play therein and having a ulcrum connection to said body at its lower end so that said outter may be rocked laterally into and out of expanded position, means tending to move said cutter toward said ramp, a catch secured to said cutter and having an outer lateral bearin surface, the tip of said catch'engaging said ramp to cause said cutter to be rojected upon upward movement thereof mto expanded position, and a longitudinally movable latch connected to said body having a retaining surface complementary to and engaging the bearing surface on said catch to prevent outward lateral displacement of said cutter, said latch and said body having engaging bearing surfaces stepped so that said atch will be 0 set laterally outward in upper position and inset in lower position. i

12. In an underreamer, the combination of a body having a longitudinally extending cavity in its periphery with an outwardly sloping ramp at its upper end and a lateral support surface above said ramp, a cutter accommodated in said cavity for longitudinal a lay therein and having a connection to said dy so that it may be moved laterally thereon into and out of expanded position, means tending to move said. cutter upward toward said ramp, a catch secured to said cutter and having an outer lateral bearing surface, the tip of said catch engaging said ramp to cause said cutter to be rojected upon upward movement thereof into expanded position, said catch in expanded position overlapping and, bearing against said support surface, and a longitudinally movable latch connected to said body having a retaining surface complementary to and engaging the bearing surface on said catch to prevent outward lateral w dis lacement of said cutter, said latch and sai body having engaging bearing surfaces stepped'so that said latch will be offset laterally outward in upper position and inset in lower position. 13. In an underreamer, the combination of a body having a longitudinally extending cavity in its periphery with an outwardly sloping ram at its upper end and a lateral support sur ac'e above said ramp, a cutter e0 accommodated in said cavity for longitudinal play therein and having a fulcrum connection to said body at its lower end so that it may be rocked laterally into and out of expanded position, means tending to move said 66 cutter toward said ramp, a catch secured to said cutter and having an outer lateral hearing surface, the tip of said catch engaging said ramp to cause said cutter to be projected upon upward movement thereof into expande position, said catch in expanded position overlapping and bearing against said suport surface, and a longitudinally movable atch connected to said body having a retaining surface complementary to and engaging the bearing surface on said catch to prevent outward lateral dis lacement of'said cutter, said latch and sai body having engaging bearing surfaces stepped so that said latch will be offset laterally outward in upper position and inset in lower position.

14. An underreamer comprising a body, a cavity in the periphery thereof, an elongated cutter member accommodated in said cavity for longitudinal and lateral play, means to hold one end of said cutter member against lateral-displacement in relation to said body,

an outwardly offset bearing surface in said cavity for the other end of said cutter member to rest against whereby in one longitudinal position said cutter member rests thereagainst and is disposed in projected position and in the other longitudmal position said cutter member is retracted, a latch on said body longitudinally movable and having a lateral bearing agalnst said other end of said cutter member, said latch and said body having engaging bearing surfaces disposed so that in one longitudinal position of said latch corresponding to the like longitudinal position of said cutter member saidlatch will be offset laterally outward and hold said cutter member against lateral displacement.

In witness that I claim the foregoing I have hereunto subscribed my name this 20th day of September, 1928.

ROLAND R. CRUM.

III 

